Since power semiconductors dissipate a great deal of heat, there is and has been a need for a means to cool such components to avoid overheating and thus avoid breakdown of the system in which the power semiconductors operate. Heretofore, such power semiconductors have been liquid cooled with either an insulating-type liquid or purified water. Cooling liquids such as insulating liquids and purified water have been used because it is believed that such liquids are not and do not become conductive during operation, and thus prevent the danger of an accidental fault or operation, and thus prevent the danger of an accidental fault or breakdown of the system in which the power semiconductors operate.
It has been found, however, that insulating liquids are not very efficient heat dissipators and thus are not as desirable as water for cooling such systems. Moreover, it has been found that water is only an excellent insulator in its nonconductive state, and that since water is a universal solvent it is very easy for nonconductive water to quickly enter into an impure, or electrically conductive state, because another attribute of water's being a universal solvent is that it will dissolve almost any substance over time, including substances which make water conductive. This can have catastrophic effects on the high power semiconductor equipment of interest. As a result, there is a need for a way of immediately indicating when such nonconductive water in a cooling system degrades to a conductive state so that the cooling system can be shut down to make the water nonconductive, and thus immediately prevent catastrophic system breakdown.